Sandals and methods and machines for their manufacture

ABSTRACT

The sandal is made of a foam rubber or a foam plastic sole within which a central portion of a single-piece fastening strip of a non-moldable material is embedded. The sole is manufactured in a mold having lateral recesses for insertion of the fastening strip prior to the molding process.

United States Patent Brunner 51 Oct. 17, 1972 [54] SANDALS AND METHODSAND 1 References Cited MACHINES FOR THEIR MANUFACTURE UNITED STATESPATENTS lnvenor: Brunner, Vienna Austria 1 SChO" 3,468,040 9/1969Fukvoka ..36/l 1.5 [731 Ass'gnw semlel"t Ostemichisch 3,552,039 1/1971Fukvoka ..36/l 1.5 QFI fw F? Gummiwer' 3,228,124 1/1 966 Schwarz ..36/l1.5 3,577,662 5/1971 Fukvoka ..36/] 1.5

Filed: March 6, 1970 Appl. No.: 17,186

Foreign Application Priority Data March 6, 1969 Austria 2198 U.S.CI..... ..36/11.5 Int. Cl. ..A43b 3/12 Field of Search .36/25 R,l 1.5,14

Primary Examiner-Patrick D. Lawson Attorney-Ernest F. Marmorek [5 7]ABSTRACT The sandal is made of a foam rubber or a foam plastic solewithin which a central portion of a single-piece fastening strip of anon-moldable material is embedded. The sole is manufactured in a moldhaving lateral recesses for insertion of the fastening strip prior tothe molding process.

10 Claims, 10 Drawing Figures PATENTEDnm 11 m2 3.698.108

sum 2 or 2 F166 Fla? This invention relates generally to sandals, and tothe methods of and machines for their production.

More particularly, this invention relates to a sandal having a sole of amoldable material such as foam rubber or plastic, preferablypolyurethane, and a fastening member of a non-moldable material in theform of a leather belt, textile stripor latchet, for example.

Known sandals of this type are made of a single or multilayer sole towhich a fastening belt or a heel supporting member is stiched orcemented. The disadvantage of such sandals resides in that the fasteningmember gets loose or even completely torn off after a certain time ofuse.

There are also known sandals having a two-layer sole and a fasteningmember attached therebetween. This embodiment has the disadvantage thatdue to the repeated tension stress occuring particularly in the area ofthe fastening member, the individual layers of the,

sole frequently get apart or disintegrate. When manufacturing sandals ofthis kind, fastening means must be first stitched or cemented to onelayer of the sole and, subsequently, the second layer is attached to thefirst one.

Furthermore, there are known sandals made of a plastic material such aspolyvinylchloride (PVC) where the sole together with the fastening stripare formed as a single piece. The disadvantage of this molded sandal isin that the fastening members of plastic material are susceptible todamage and cannot be restored.

It is, accordingly, one of the objects of this invention to provide asandal which will avoid the above mentioned drawbacks of the prior art.i

In particular, it is an object of the invention to provide a sandalwhich is secure against tearing off the fastening member.

It is also an object of this invention to provide a sandal that is easyto manufacture.

A further object of this invention is to provide a method of and adevice for the manufacture of sandals.

According to this invention, the above objects are attained by providinga single-layer sole of a moldable material in which an intermediateportion of a singlepiece fastening member is embedded. The moldablematerial of the sole is preferably foam rubber or foam plastic, whereasthe fastening member is made of a non-moldable material, such asleather, textile and the like. In a further development of thisinvention, the top and bottom surfaces of the sole may be provided witha protective coating such as a layer of leather, artificial leather,etc.

Due to the embedding of the fastening member simultaneously with themolding of the sole, the process of stitching or cementing of thefastening means as well as of respective layers of the sole can now beavoided. To improve the anchorage of the intermediate portion of thefastening member within the body of the sole, this portion can beprovided with holes or with projections, or simply roughened.

In another modification of this invention, the sole and the fasteningmember are manufactured and assembled separately. For this purpose, thesole is provided with a transverse slit through which the fastening beltis drawn and secured in place by means of rivets, screws and the like.The intermediate portion of the fastening belt can bealso anchored by aplastic seal introduced into the slit. The position of the embeddedintermediate portion defined the configuration of the projectingportions of the fastening member. For example, if the embedded portionof the fastening belt in its breadth is arched or bulged downwards, themarginal portions of the free ends of the belt become bent upwardly withrespect to their center line area and, consequently, at walking theedgesof the fastening belt do not cut into the foot. If the embedded portion,on the other hand, is arched upwardly, the fastening belt will bettercounteract the tension stress in the body of the sole. Such acountertension is advantageous especially in very flexible soles.

The sandals according to this invention are manufactured preferably inthe manner that the fastening member is first inserted into a transverserecess that is provided in the bottom mold unit, and sealed by means oflateral blocks that are profiled according to the contour of theadjacent portion of the: sole. Subsequently, the bottom mold unit isfilled up with the mixture of the material to be molded, and the topmold unit is seated on the bottom mold unit. It is also possible firstto close the mold and then fill it up by injecting the plastic material.As a result, the intermediate portion of the fastening member becomesintegrallyembedded approximately in the middle of the vertical dimensionof the sole.

To make variations in the types of the manufactured sandals, it may beadvantageous to produce the soles separately from the fastening members.In this case the soles are manufactured with a transverse slit orpassage for the additional insertion of the fastening member. Theremovable insert, the recess as well as the inside walls of the mold,must be, of course, painted with a separating means. After thecompletion of the molding process, the insert is removed from thefinished sole and the fastening member can be introduced into theresulting slit. If the soles are manufactured from polyurethane, it ispossible to make the insert from polytetrafluorethylene, for example. Ifthe sole is to be provided with a protective coating, a foil of theprotective coating material is clamped prior to the molding processbetween the top and bottom mold units.

As mentioned above, the mold for manufacturing the sandals of thisinvention has a top and a bottom unit. The bottom unit is provided witha transverse recess in the area of, the fastening strip. Each side ofthis recess is closed by a removable sealing block which is profiledaccording to the corresponding outline section of the sole. The sealingblocks may, have a tapering, wedgelike configuration, and may beintegral with the top mold unit.

BRIEF DESCRIPTION OF SEVERAL VIEWS OF THE DRAWING:

For a better understanding of the invention, reference is made to thefollowing description of several exemplary embodiments, taken inconjunction with the figures of the accompanying drawing, in which:

FIG. 1 is a fragmentary side elevational view of the sandal of thisinvention;

FIG. 2 is a plan view of the sandal. of FIG. 1;

FIG. 3 is a sectional view of a mold for the manufacture of sandals ofthis invention;

FIG. 4 is a plan view of the bottom part of the mold of FIG. 3;

FIG. is a side elevational view of a mold for manufacturing soles of thesandals according to the invention;

FIG. 6 is a plan view of the bottom mold unit of the mold of FIG. 5;

FIG. 7 is a fragmentary plan view of a modified bot- DETAILEDDESCRIPTION Referring now to FIGS. 1 and 2, the sandal according to theinvention comprises a sole 1 and a fastening belt 2. The sole 1 can bemade of foam rubber or a suitable plastic material such as foam-likepolyurethane, for example. The upper surface of the sole 1 is covered bya protective coating 3 which may be a layer of a material that iscomfortable for the foot, such as leather, textile, artificial leatherand the like. According to one feature of this invention, the fasteningmember is a single-piece fastening belt 2 the intermediate portion ofwhich is embedded within the body of the sole 1. The free end portionsof the fastening belt 2 are conducted around the foot and can be coupledone to another in a conventional manner by an adjustable catch orbuckle, for instance. As seen in FIG. 2, the fastening belt 2 passestransversely through the middle of the height of the sole 1 in the areaof the forepart of the foot. The single-.

piece fastening member is not limited, of course, to the form of theleather belt 2, but it can have the form of a textile strap, latchet oranother suitable supporting means.

The mold for the manufacture of the sandals of this invention, as shownin FIGS. 3 and 4, comprises a bottom mold unit 4, and a top mold unit 5.At the region of the fastening belt 2, the bottom mold unit 4 haslateral recess 6 provided for receiving sealing blocks 7. Inmanufacturing the sandals, the intermediate portion of the fasteningbelt 2 is first inserted across the bottom mold unit 4 to pass throughthe recesses 6, and the removable sealing blocks 7 are placed inposition against the projecting portions of the fastening belt 2. At thesame time it is necessary to check that the fastening belt 2 does notprotrude into the contact with the inside surface of the mold. In asubsequent step, a measured quantity of filling material such as amoldable foam rubber, polyurethane or similar foam-like plasticmaterial, is introduced into the bottom mold unit 4, and covered by thetop mold unit 5. If the sandals are to be produced by an injectionmolding process, the mold must be provided with an injection channel,and the mold is assembled of the bottom and top mold units 4 and 5 priorto the introduction of the molding material. In order to insure aslip-proof adherence of the fastening belt 2 to the body of the sole 1even if non-adhesive material is employed, it is advisable that aplurality of holes be created in the intermediate portion of the belt 2so that the molded material passing through the holes will producebridges reinforcing the anchorage.

As illustrated in FIGS. 5 and 6, the mold can be modified for themanufacture of soles l separately from the manufacture of the entiresandal. For this purpose, the sole 1 is first provided with a transverseslit or channel into which the fastening belt can be additionallyinserted. The modified bottom mold unit 8 is, therefore, provided with atransverse channel 9 passing through the lateral sides of the mold 8 inthe area of the fastening means. Prior to the injection of the moldingmaterial, a strip-like removable insert 10 is placed into the channel 9to cross the bottom mold unit 8. The insert 10 preferably has a taperingconfiguration so that a sufficient sealing of the channel 9 might beattained. Moreover, to prevent the insert 10 and all inside surfaces ofthe mold from sticking to the sole, they must be dressed by a separatingmeans.

With reference to FIG. 7, the bottom mold unit 8' is provided in thearea of the fastening member with laterally closed recesses into which aremovable striplike insert 10 is placed from above to cross the bottommold unit 8, thereby facilitating the assembly and disassembly of themold. In this case, however, the top mold unit must be provided withprofiled bosses or blocks to define the contour of the sole in the areaof the recesses above the top surface of the insert 10'.

To avoid cutting of the edges of the fastening belt 2 into the foot, theembedded intermediate portion 11 of the fastening belt 2 is archeddownwardly in its breadth so that the edges of the free portions of thefastening belt 2 will become bent upwardly (FIG. 8).

In another modification, as illustrated in FIG. 9, the embeddedintermediate portion 12 of the fastening belt 2 is arched upwardly inits breadth. As a consequence, the most stressed end regions of theintermediate belt portion 12 are counteracted by an increased thicknessof the sole body so that even an extremely flexible material for thesole 1 can be employed.

FIG. 10 illustrates a modification of the sandal of this invention, inwhich an additional fastening member 13 for supporting the heel isprovided. This single piece fastening member 13 is attached to the sole1 in the same manner as the fastening belt 2 at the fore of the foot. Inaddition to the protective coating 3, the bottom surface of the sole 1can also be provided with protective layer 14 of a wear resistantmaterial, such as hard rubber, for example.

I wish it to be understood that I do not desire to be limited to theexact details of construction shown and described, for obviousmodifications will occur to a person skilled in the art.

Having thus described the invention, what I claim as new and desire tobe secured by Letters Patent, is as follows:

1. A sandal, especially health sandal, including a sole comprising asingle layer of molded elastic material, and

an upper of non-moldable material including portions interconnectedwithin said layer, and embedded in, and thereby held slip-proof in, saidlayer and reaching from side to side through said layer.

2. A sandal according to claim 1 further comprising a layer disposed onthe top surface of said sole.

3. A sandal according to claim 1 wherein said interconnected portions ofsaid upper within said sole are provided with holes.

4. A sandal according to claim 1 wherein said interconnected portions ofsaid upper within said sole are provided with projections.

5. A sandal according to claim 1 further comprising additional fasteningmeans securing said sole to said interconnected portions of said upperembedded within said sole.

6. A sandal according to claim 1 wherein said upper is introduced intothe side surfaces of said sole.

7 A sandal according to claim 6 wherein said upper is directed to saidside surfaces of said sole substantially parallel to the bottom surfaceof said sole and the transverse cross-section of said upper at leastnear said sole surfaces has an arched shape.

8. A sandal according to claim 1 wherein said interconnected portions ofsaid upper are anchored in said sole by shaping.

9. A sandal as claimed in claim 1 wherein said portions are integrallyinterconnected within said sole.

10. A sandal as claimed in claim 9 wherein said upper is a belt.

1. A sandal, especially health sandal, including a sole comprising asingle layer of molded elastic material, and an upper of non-moldablematerial including portions interconnected within said layer, andembedded in, and thereby held slip-proof in, said layer and reachingfrom side to side through said layer.
 2. A sandal according to claim 1further comprising a layer disposed on the top surface of said sole. 3.A sandal according to claim 1 wherein said interconnected portions ofsaid upper within said sole are provided with holes.
 4. A sandalaccording to claim 1 wherein said interconnected portions of said upperwithin said sole are provided with projections.
 5. A sandal according toclaim 1 further comprising additional fastening means securing said soleto said interconnected portions of said upper embedded within said sole.6. A sandal according to claim 1 wherein said upper is introduced intothe side surfaces of said sole.
 7. A sandal according to claim 6 whereinsaid upper is directed to said side surfaces of said sole substantiallyparallel to the bottom surface of said sole and the transversecross-section of said upper at least near said sole surfaces has anarched shape.
 8. A sandal according to claim 1 wherein saidinterconnected portions of said upper are anchored in said sole byshaping.
 9. A sandal as claimed in claim 1 wherein said portions areintegrally interconnected within said sole.
 10. A sandal as claimed inclaim 9 wherein said upper is a belt.